The hypothalamic-pituitary-adrenal (HPA) axis and the inflammatory response system have been suggested as pathophysiological mechanisms implicated in the etiology of major depressive disorder (MDD). ...Although meta-analyses do confirm associations between depression and these biological systems, effect sizes vary greatly among individual studies. A potentially important factor explaining variability is heterogeneity of MDD. Aim of this study was to evaluate the association between depressive subtypes (based on latent class analysis) and biological measures. Data from 776 persons from the Netherlands Study of Depression and Anxiety, including 111 chronic depressed persons with melancholic depression, 122 with atypical depression and 543 controls were analyzed. Inflammatory markers (C-reactive protein, interleukin-6, tumor necrosis factor-α), metabolic syndrome components, body mass index (BMI), saliva cortisol awakening curves (area under the curve with respect to the ground (AUCg) and with respect to the increase (AUCi)), and diurnal cortisol slope were compared among groups. Persons with melancholic depression had a higher AUCg and higher diurnal slope compared with persons with atypical depression and with controls. Persons with atypical depression had significantly higher levels of inflammatory markers, BMI, waist circumference and triglycerides, and lower high-density lipid cholesterol than persons with melancholic depression and controls. This study confirms that chronic forms of the two major subtypes of depression are associated with different biological correlates with inflammatory and metabolic dysregulation in atypical depression and HPA-axis hyperactivity in melancholic depression. The data provide further evidence that chronic forms of depressive subtypes differ not only in their symptom presentation, but also in their biological correlates. These findings have important implications for future research on pathophysiological pathways of depression and treatment.
It has been hypothesized that hypovitaminosis D is associated with depression but epidemiological evidence is limited. We investigated the association between depressive disorders and related ...clinical characteristics with blood concentrations of 25-hydroxyvitamin D 25(OH)D in a large cohort. The sample consisted of participants (aged 18-65 years) from the Netherlands Study of Depression and Anxiety (NESDA) with a current (N=1102) or remitted (N=790) depressive disorder (major depressive disorder, dysthymia) defined according to DSM-IV criteria, and healthy controls (N=494). Serum levels of 25(OH)D measured and analyzed in multivariate analyses adjusting for sociodemographics, sunlight, urbanization, lifestyle and health. Of the sample, 33.6% had deficient or insufficient serum 25(OH)D (<50 nmol l(-1)). As compared with controls, lower 25(OH)D levels were found in participants with current depression (P=0.001, Cohen's d=0.21), particularly in those with the most severe symptoms (P=0.001, Cohen's d=0.44). In currently depressed persons, 25(OH)D was inversely associated with symptom severity (β=-0.19, s.e.=0.07, P=0.003) suggesting a dose-response gradient, and with risk (relative risk=0.90, 95% confidence interval=0.82-0.99, P=0.03) of having a depressive disorders at 2-year follow-up. This large cohort study indicates that low levels of 25(OH)D were associated to the presence and severity of depressive disorder suggesting that hypovitaminosis D may represent an underlying biological vulnerability for depression. Future studies should elucidate whether-the highly prevalent-hypovitaminosis D could be cost-effectively treated as part of preventive or treatment interventions for depression.
Hardeveld F, Spijker J, De Graaf R, Nolen WA, Beekman ATF. Prevalence and predictors of recurrence of major depressive disorder in the adult population.
Objective: Knowledge of the risk of ...recurrence after recovery of a major depressive disorder (MDD) is of clinical and scientific importance. The purpose of this paper was to provide a systematic review of the prevalence and predictors of recurrence of MDD.
Method: Studies were searched in Medline en PsychINFO using the search terms ‘recur*’, ‘relaps*’, ‘depress*’, ‘predict*’ and course.
Results: Recurrence of MDD in specialised mental healthcare settings is high (60% after 5 years, 67% after 10 years and 85% after 15 years) and seems lower in the general population (35% after 15 years). Number of previous episodes and subclinical residual symptoms appear to be the most important predictors. Gender, civil status and socioeconomic status seem not related to the recurrence of MDD.
Conclusion: Clinical factors seem the most important predictors of recurrence. Data from studies performed in the general population and primary care on the recurrent course of MDD are scarce.
Knowledge of the risk of recurrence after recovery from major depressive disorder (MDD) in the general population is scarce.
Data were derived from 687 subjects in the general population with a ...lifetime DSM-III-R diagnosis of MDD but without a current major depressive episode (MDE) or dysthymia. Participants had to be at least 6 months in remission, and were recruited from The Netherlands Mental Health Survey and Incidence Study (NEMESIS), using the composite international diagnostic interview (CIDI). Recency and severity of the last MDE were assessed retrospectively at baseline. Recurrence of MDD was measured prospectively during the 3-year follow-up. Kaplan-Meier survival curves were used to measure time to recurrence. Determinants of time to recurrence were analyzed using proportional hazard models.
The estimated cumulative recurrence of MDD was 13.2% at 5 years, 23.2% at 10 years and 42.0% at 20 years. In bivariate analysis, the following variables predicted a shorter time to recurrence: younger age, younger age of onset, higher number of previous episodes, a severe last depressive episode, negative youth experiences, ongoing difficulties before recurrence and high neuroticism. Multivariably, younger age, a higher number of previous episodes, a severe last depressive episode, negative youth experiences and ongoing difficulties remained significant.
In this community sample, the long-term risk of recurrence was high, but lower than that found in clinical samples. Subjects who had had an MDE had a long-term vulnerability for recurrence. Factors predicting recurrence included illness- and stress-related factors.
Peen J, Schoevers RA, Beekman AT, Dekker J. The current status of urban–rural differences in psychiatric disorders.
Objective: Reviews of urban–rural differences in psychiatric disorders conclude ...that urban rates may be marginally higher and, specifically, somewhat higher for depression. However, pooled results are not available.
Method: A meta‐analysis of urban–rural differences in prevalence was conducted on data taken from 20 population survey studies published since 1985. Pooled urban–rural odds ratios (OR) were calculated for the total prevalence of psychiatric disorders, and specifically for mood, anxiety and substance use disorders.
Results: Significant pooled urban–rural OR were found for the total prevalence of psychiatric disorders, and for mood disorders and anxiety disorders. No significant association with urbanization was found for substance use disorders. Adjustment for various confounders had a limited impact on the urban–rural OR.
Conclusion: Urbanization may be taken into account in the allocation of mental health services.
Evidence strongly suggests that depression and type 2 diabetes are associated, but the direction of the association is still unclear. Depression may occur as a consequence of having diabetes, but may ...also be a risk factor for the onset of type 2 diabetes. This study examined the latter association by reviewing the literature and conducting a meta-analysis of longitudinal studies on this topic.
Medline and PsycInfo were searched for articles published up to January 2005. All studies that examined the relationship between depression and the onset of type 2 diabetes were included. Pooled relative risks were calculated using fixed and random effects models. To explore sources of heterogeneity between studies, subgroup analyses and meta-regression analyses were performed.
Nine studies met our inclusion criteria for this meta-analysis. The pooled relative risk was 1.26 (1.13-1.39) using the fixed effects model and 1.37 (1.14-1.63) using the random effects model. Heterogeneity between studies could not be explained by (1) whether studies controlled for undetected diabetes at baseline; (2) the method of diabetes assessment at follow-up; (3) the baseline overall risk of diabetes in the study population; and (4) follow-up duration.
Depressed adults have a 37% increased risk of developing type 2 diabetes mellitus. The pathophysiological mechanisms underlying this relationship are still unclear and warrant further research. A randomised controlled study is needed to test whether effective prevention or treatment of depression can reduce the incidence of type 2 diabetes and its health consequences.
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